Immunophenotypic analyses of CD34+ cell subsets in bone marrow from HIV‐infected patients during highly‐ active antiretroviral therapy

AbstractBackground Because increased bone marrow lymphopoiesis might contribute to immunologic reconstitution during highly‐active antiretroviral therapy (HAART), we examined the effect of HAART on CD34+ cell subsets in bone marrow from HIV‐infected patients.Materials and Methods In 12 HIV‐infected patients, bone marrow and peripheral blood were collected before then 4 and 26 weeks after initiating HAART. Bone marrow in 28 HIV‐seronegative controls was also examined. Immunophenotypic analyses of CD34+ cell subsets in bone marrow were performed by flow cytometry.Results Our main findings in bone marrow were: (i) HIV‐infected patients had increased proportions of CD34+ cells expressing T‐ and B‐cell markers before initiating HAART; (ii) in contrast, these patients had decreased proportions of CD34+ cells expressing myeloid‐associated markers; (iii) although HAART induced an increase in peripheral T‐cell counts, the percentage of CD34+ cells expressing T‐cell markers tended to decrease during such therapy; (iv) HAART induced a decrease in serum IgG accompanied by a slight decrease in the proportion of CD34+ cells expressing B‐cell markers; (v) in contrast, HAART induced a significant increase in peripheral granulocyte counts, accompanied by a slightly increased proportion of CD34+ cells expressing myeloid‐associated molecules.Conclusion Our findings are compatible with an HIV‐related block in T‐cell differentiation, leading to accumulation of T‐cell progenitors in bone marrow, and such a block may be removed by HAART.